Nonoverfill device



May 8,, 1945. L. L. DRQWN Y NONOVERFILL DEVICE Filed May 27, 1942 wh/dwf $55 3 16;, ATTORNEYS.

Patented May 8, 1945 N ONOVERFILL DEVICE Lyle L. Drown, Iietroit, Mich.,assignor to General Motors Corporation, Detroit, Mich, a corporation ofDelaware Application May 27, 1942, semi: No. 444,643

1 Claim.

This invention relates to improvement in nonoverfill devices for storagebatteries and other electrolytic cells, and is especially useful instor-, age batteries for 'automobileuse.

The primary object of the invention is to provide simple and reliableand inexpensive'means for automatically closing the filling opening whenthe plug is removed to permit the cell to be filled only to the requiredlevel .and insuring an adestorage battery electrolyte and said ball beforced through a restricted opening in the filler opening and expand toits normal size after it passesthrough the opening and adapted, when thevent plug is removed and the electrolyte level is raised 34 about thefiller opening,

normally covered by electrolyte, the normal level of which is indicatedat 23. The cell is provided with the usual internal shoulders, notshown, upon which rest a cell cover 24. The joint between the cell andcover is sealed with the usual sealing compound, not shown.

The cover in the present'instance is shown as having a filler openinghaving a boss 3| above the surface of the cover which is preferablyinternally threaded as at 32 for engagement with external threads of avent cap 33. The cover 24 is formed to provide a tubular extension orskirt This tubular extension projects downwardly to a predetermineddistance, but spacedfrom the top edges of the plates of the plateassembly 2|. The tubular extension 34' is provided with an internalledge 35 defining a restricted opening 36. The under surface of theledge serves as a valve seat for a floating ball 3l.. The ball is'madeof any suitable substance capable. of floating, and resistant to thestorage battery electrolyte. It may be made,

' for example, of soft rubber or other soft material.

to the proper level, to engage a seat and close.

the restricted opening. When the vent plugis attached to the cover theplug forces the floating panying drawing wherein a preferred embodimentof the present invention is clearly shown.

In the drawing: I Fig. l is a fragmentary sectional view of a cell covershowing a, floating rubber ball valve held in a closed position by theliquid, the filler plug or cap being removed.

Fig. 2 is a view similar to Fig. 1 but showing a vent plu screweddowninto its well for closing the latter.

The material should be such as to yield sufficiently to seal a seat whenthe electrolyte level in the cell has been reached so that the liquidwill rise rapidly in the filling opening above the ball to give a signalto the operator that the filling opdimensions of the restricted opening36 so as to provide for a sealing fit therebetween and thecross-dimensions of the ball are less than the cross dimensions of thetubular extension 31 so as to provide for considerable play of the ballwithin the confines of the tubular extension below the seat. When liquidis poured into the cell the electrolyte level will rise until the ballengages the seat to seal the restricted opening 36.

This ball together with the film-generally formed on the surface of theball will seal the restricted opening that airwill be trapped below theseat and the level and also in the space exterior of the tubularextension and the underside of the Fig. 3 is a. fragmentary sectionalview showing cover above the electrolyte level. I

The rubber ball is preferably assembled with thc'ell after all of theother elements ofthe cell have been assembled and sealed. The ball isfirst inserted into the filler opening and-rests upon the upper side ofthe ledge 35. The ball is then manner 'illustrated in Fig. 3.

forced through the opening by a tool 40 in the served that the uppersurface 4| of the ledge 35 which merges with the walls of the restrictedopening is rounded as at 42 in order to facilitate the forcing of theball through the opening and also to prevent the ball from being marredwhile. it is being forced through the opening 36.

When the ball passes through the opening the ball will expand to itsnormal size due to itsown resiliency and occupy the space betweenthe'seat and the upper edges of the plates of the plate: assembly 2|which extend across the lower end of the tubular extension. It will beobserved that the space between the lower edge of the tubular extensionis considerably less than the cross dimensions of the ball, thus theball cannot pass from the confines of the tubular extension should thelevel of the liquid drop below the up-, per-edges of the plates 2 I. Theball in that case would rest upon the plates as indicated by thedot-and-dash circle in Fig. l. The lower edge of the ledge is preferablyformed with tapered or cup-shaped surface 45, said surface acting as .aguide to direct positively the ball 3'! over the opening 36 as theelectrolyte level rises, thus insuring that the opening 36 will besealed by the ball float valve when the desired electrolyte level hasbeen reached.

The ball is moved away from the seat by the vent plug 33 having anextension 46 adapted to project through the restricted opening 36 andengage the ball 3! forcing same downwardly into the electrolyte, as'inFig. 3, and maintain same away from the seat permitting the trapped airand also gases to pass through the by-pass passages 38 and through therestricted opening 36 and thence through a duct 42 in the vvent plug 30to the-atmosphere, i .It will be seen that the present structure isextremely simple and inexpensive. Further it simplifies the assembly andcharging procedure at the factory in that the ball valve can be left Itwill be obas herein disclosed, constitutes a preferred form, it is to beunderstood that other forms might be adopted, all coming within thescope of the claims which follow.

What is claimed is as follows: In combination with a container forliquid and including plates normally covered by the liquid;

a cover having a filling opening adapted to receive and retain a ventplug, said cover having a skirt depending therefrom about the fillingopening and extending below the normal liquid level with the lower endthereof spaced from the plates, said skirt having an inwardly extendinga rib defining an annular opening smaller than the out until the batteryis complete and ready for shipment if so desired.

While the embodiment of the present invention skirt at a point above thenormal liquid level, said rib joining the skirt with frusto-conical'sur-' faces said skirt having a by-pass above the liquid level andbelow the smaller opening providing communication between the spaceoutside the skirt and the space within the skirt above the level butbelow the smaller opening; a valve normally floating on the surface ofthe liquid and guided by the lower conical surface of the rib to sealthe smaller opening to prevent communication from the space below therib to outside atmosphere when the plug is removed and the liquid is atits normal level, said valve comprising a soft rubber ball having across dimension larger than the smaller opening and also the spacebetween the lower edge of the skirt and. the 7 plates and adapted to beforced through the smaller opening under distortion and then expand tonormal size below the rib and float on the liquid within the confines ofthe skirt, said ball contacting the upper conical surface of the .rib tofacilitate distortion of the ball when same is being forced through thesmaller opening; and a readily attachable and detachable vent plughaving an extension projecting loosely through the smaller opening whenthe p u i attached d moving the ball into the liquid to open the smalleropening to establish communication between the spaces above'and belowthe rib and the atmosphere through the vent plug.

LYLE L. DROWN.

